1. Field of the Invention
The present invention relates to an electronic component having a built-in inductor which comprises a substrate and an inductance element provided therein, and more particularly, it relates to an electronic component having a built-in inductor which comprises an inductance element of a ferromagnetic metal.
2. Description of the Background Art Conventional electronic components comprising substrates and inductance elements provided therein are manufactured by the following methods (1) to (3):
(1) A method of providing an inductance element, which is prepared by forming a conductor in a ferrite member with conductor paste, in an unfired ceramic substrate and there-after simultaneously firing the substrate material and the conductor paste, thereby obtaining a substrate having a built-in inductance.
(2) A method of providing a ferrite layer, which is previously formed with a conductor consisting of conductor paste therein, in an unfired ceramic substrate and firing the unfired ceramic substrate with the ferrite layer and the conductor paste.
(3) A method of utilizing an inductance which is generated from a conductor provided in a substrate, without particularly employing a ferromagnetic substance.
Each of the methods (1) and (2) comprises the step of simultaneously firing the ceramic material forming the substrate and the ferrite material. Therefore, the ferrite and ceramic components are mutually diffused in the firing, to disadvantageously reduce electric characteristics. In particular, iron oxide which is contained in the ferrite material is quickly diffused to reduce insulation resistance upon diffusion in an insulating ceramics. Thus, it is necessary to suppress the reduction of insulation resistance caused by such diffusion of the iron oxide.
In the method (3) utilizing an inductance which is generated from a conductor provided in a substrate without employing a ferromagnetic substance, on the other hand, it is necessary to increase the length of the conductor part for forming the inductance, and hence the component size is inevitably increased.